High-strength coating film manufacturing technology through a solution process has grown steadily with the development of scientific and industrial standards. In particular, various studies to combine the functionality of organic materials together with the high strength properties of inorganic materials are going on through the development of organic-inorganic hybrid materials, and visible results have been applied in many places.
Up to now, the most common high-strength coating material for solution process is tetraethylorthosilicate (TEOS) based silicon solution composition, and its greatest advantage is that it can achieve surface hardness similar to a glass film through the solution process. However, because of issues such as poor stability of the coating solution and a large shrinkage occurring during the curing process, it has not been widely applied across the industry so far.
To overcome this problem, various studies on a low-temperature glass film coating structure have been proceeding, of which Korea Patent Application No. 2009-0019226 disclosed a polysilazane (R2SiNH)n. The silazane structure is a compound capable of naturally producing a silica structure at a low temperature, thereby increasing the silica content and achieving the high hardness of a glass film, and attempts to apply this have been made in many fields through a spray coating method, etc. However, this structure is very difficult to secure its reproducible synthesis, it is lack in stability in the air at a room temperature so that it needs numerous post-treatment processes to be done in its storage process, and this disadvantage leads to the lack of economic effect as well as the stability of a material itself, imposing a great restriction on its application fields. Due to the above problems, its commercialization with other functional materials is difficult, and it is difficult to secure a long-term stability and storage stability. Accordingly, its application is currently being made in a limited level. To overcome its restricted application limit, a new high-strength chemical structure for solution process must be designed first in consideration of the following aspects:
1. having a chemical structure with an excellent storage stability, but being able to change into a stable cured product during a curing process,
2. minimizing a change in surface characteristics such as moisture absorption after the film formation, and
3. having a good compatibility with various functional materials.
In addition, for its limitless application, it should show an excellent solution dispersion property to achieve a high compatibility with functional media.